Gaseous electric discharge lamp device



April 1939- w. HANLEIN ET AL 2,994 7 GASEOU S ELECTRIC DISCHARGE LAMP DEVICE Filed March 23, 1957 INVENITORS Walt er Hanlem Wilhelm Hagen Hermann Kreffc. BY

ATTOR N EY Patented Apr..4,1939- it H I 2,152,994

UNITED STATES PATENT OFFICE Walter Hiinlein, Berlin-Spandau, Wilhelm Hagen, Berlin, and Hermann Kreflt, Berlin-Friedriclis-- hagen, Germany, assignors to General Electris Company, a corporation oi New York Application March 23, 1937, Serial No. 132,640

.In Germany March 30, 1936 4 Claims. (Cl. 176-422) The present invention relates to gaseous elecmercury vapor, electric discharge lamps operattric discharge lamp devices generally and more ing with elevated container temperatures. Such particularly the invention relates to'vapor dis-. glasses have a softening temperature of about charge lamp devices operating with elevated con- '1,000 C., are more easily workable than quartz tainer temperatures and with correspondingly and do not devitrify as rapidly as quartz. \The 5 elevated vapor pressures, such as a vapor presultra violet transmission of the glass is comparasure in the order of atmospheres, similar to that ble to that of quartz. Perhaps the chief advandisclosed in co-pending application, Serial No. tags of the glasses of the invention over quartz 120,066, filed January 11, 1937, inventors Wilis that while the coefiiclent of expansion thereof l helm Hagen and Wolfgang Thouret. is low enough to avoid breaking strains under I'he containers of-such devices are at a temlarge differences of temperature it is such that perature of about 600 'C. and higher during the current leads of tungsten or molybdenum can operation of the device and large differences in be sealed directly into a lamp container consisttemperature between different parts of the coning of such glass.

tainer exist under service conditions. It is de- In the following table various glass composi- 15 sirable, since the gaseous atmosphere oi the tions which we have discovered are useful as lamp consists of, or comprises mercury vapor, to container glasses for gaseous electric discharge useavitreous container material which transmits lamp devices are listed, together with the coboth the visible and the ultra violet light emitted eilicient of expansion measured at 50 C. and

2 by the excited mercury vapor during the operathe softening temperature oi. each glass compo- 2 tion of the device. It has been customary in the sltion. The softening temperature of each glass art, heretofore, to make the lamp container of is the temperature at which a rod 10 cm. long fused silica, or quartz, this being the only ma and about 3 mm. in diameter resting on two terial available which would successfully meet knife edges begins to bend.

the above requirements. Quartz containers are 25 diillcult and expensive to fabricate due to the Exlgnision high softening temperature of the quartz and the we c sommm low coefllcient of expansion thereof which make 9 Bao 'fid -i point 8 the sealing of current leads therein, such as 30 tungsten or molybdenum leads, complicated. h 80 The useful operating life of such lamps having a. quartz containers is not as long as could be de- 5 gsired due to the fact that the quartz tends to 8 8 1 1.75 175 11 1040 devitrify at high container temperature, such as 4 3 75 temperaturesfrom about 70 C. to about 870 Y 85 C., and the transmissivity thereof for the light In the drawing accompanying and forming emitted by the gaseous electric discharge rapidly P Of this s ion a aseous electric disdjmlmshes charge lamp device having a container consisting The object of the invention is to an 11 Of One 01' glasses disclosed above 18 Shown expensive gaseous electric discharge lamp device in a side elevation view- 40 capable of operation with an elevated container Referring the wing the gasemls electric temperature and having a long useful operatin discharge lamp device comprises an elongated, life. Another object of the invention is to pro-" tubular container having current leads 2 and vide a vitreous t i 1 1.339, contagner sealed therein, one in each. end thereof. Said material for gaseous electric discharge devices n leads 2 and consist of 811 elti 45 generally and particularly for such devices op- Point material, h as n n and are s aled erating' with elevated container temperatures. irec ly into the glass of container i. Said con- Further objects and advantages of the invention 811161 I h her n a Starting 8 1101188 will be apparent to those skilled in the art-from arson. 1' startin gas mixture and a quantity 4 the following particular description. of vaporizable material such as mercury, the 50 We havehi'scovered that a glass consisting of vapor of which is luminosity producing during from 80 to 98% silica (SiO'i), from -'2 to 12% the operation of the device. The lamp starts alumina (A1201) and from 0 to 8% of alkaline as a gas lamp and operates as a vaporlamp and earth metal oxide, suchasv calcium oxide and the vapor pressure in the lamp is about'ten' barium oxide, is a good'containe'r material for atmospheres or higher during the operation or the lamp device. Theelectrodes I and l are mounted on said leads 2 and 2', respectively. Each 01 said electrodes 3 and 3' consists of a perforated, tungsten shell fllled with a mixture of aluminum oxide, tungsten and an alkaline earth metal oxide and is heated to a high electron emitting temperature by the discharge incident thereat.

Said container l consists of a glass having one of the compositions disclosed above and the gaseous electric discharge lamp is a long-lived, high eflicient, inexpensively manufactured source of visible and ultra violet light.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details g the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for example, the container I is made in other shapes, such as a spherical shape, or a small bore tube. when desired, the electrodes are mounted in other positions in the container, when desired other types or thermionic electrodes, such as those requiring a special heater source are used, when desired, and the part of the current leads in the lamp is surrounded by a tube of high melting point, insulating material to protect it from the discharge, when desired.

What we claim as new and desire to secure by Letters Patent oi the United States is:-

l. A gaseous electric discharge device comprising a container, a gaseous atmosphere therein and electrodes sealed therein, said container consisting of a glass consisting of about 80 to 98% silica (S102), about 2 to 12% alumina (A120:) and about 0 to 8% alkaline earth metal oxides.

2. A gaseous electric discharge device comprising a container, a gaseous atmosphere therein and electrodes sealed therein, said container consisting of a glass consisting of about 94.5% silica (Sig )2) and 5.5% alumina.

39A gaseous electric discharge device comprising a container, a gaseous atmosphere therein and electrodes sealed therein, said container consisting of a. glass consisting of about 93% silica ($102), alumina (A1203), 1% calcium oxide (09.0) and 1% barium oxide (BaO).

4. A gaseous electric discharge device comprising a container, a gaseous atmosphere therein and electrodes sealed therein, said container consisting of a glass consisting of about 82.5% silica (SiOz'), alumina (A1203), 3.75% calcium oxide (CaO), 3.75% barium oxide (BaO).

WALTER WILHELM I-IAGEN. HERMANN KREFFI. 

